Explanation:

For 1: The correct answer is Option c.

HCequiv CH is an alkyne having triple bond between two carbon atoms.

For 2: The correct answer is Option g.

Benzene is a cyclic compound having 6 carbon atoms, where alternate carbon atoms are bonded with a double bond (or have unsaturation)

For 3: The correct answer is Option e.

The general formula to write any alkene (having double bond) is C_nH_{2n}, where n = 1, 2, 3,4….

For 4: The correct answer is Option a.

Unsaturated hydrocarbons are the compounds having double and triple bond present between two carbon atoms. The common reaction which all unsaturated hydrocarbons undergo is addition reaction.

For 5: The correct answer is Option f.

The general formula to write any alkyne (having triple bond) is C_nH_{2n-2}, where n = 1, 2, 3,4….

For 6: The correct answer is Option d.

The hydrocarbons where a triple bond is present between two carbon atoms belong to a group known as alkyne.

For 7: The correct answer is Option b.

The general formula to write any alkane (having single bond) is C_nH_{2n+2}, where n = 1, 2, 3,4….